Device in a system operating with CAN-protocol and in a control and/or supervision system

ABSTRACT

A control supervision system incorporates a digital serial communication and modules that are mutually communicable to this and operate with CAN-protocol. A control desk can be wirelessly connected to one or more modules operating with a signal protocol which does not take into account arbitration and/or confirmation functions appearing in the CAN-system. A particular receiving communication part executes the conversion of the signal protocol to the signal protocol of the CAN-system. A device for controlling a function in a first module in a CAN-system via a wireless connection to a second module in the system is provided. A system of mutually separate units, where each unit operates with a CAN-signalling protocol, intercommunicating with an identification system in which a key allocation between the units is based upon identities that are assigned by a module in the unit or a master system is also provided.

TECHNICAL FIELD

[0001] The present invention relates to a device in a machine-controlsystem and/or process-supervision system operating with the CAN-protocolaccording to standard ISO 11898. CAN-system of this type comprisemodules which are intercommunicable via a digital serial communicationand in which a control and/or supervisory function can be realised froma first module or from a unit, which is communicable with theCAN-system, belonging to one or more second module(s) The presentinvention is a single-day application made together with Swedish patentapplication “Device in a control and/or supervision system” submitted bythe same applicant and the same inventor.

[0002] The present invention relates to a device in a machine-controlsystem or process-control system. The said system has in the presentcase been referred to as a CAN-system, since the systems in question arerequired to use the signal protocol according to CAN (Controller AreaNetwork, corresponding to standard ISO 11898). The invention in thiscase relates to those types of CAN-system comprising modules which areconnectable via a digital serial communication and in which a functionin a first module is intended to be able to be observed, stimulated orregistered at a location for the placement of the first module.Reference is also made to Swedish patent application “Device in a systemoperating with CAN-protocol”, which was submitted on the same day by thesame applicant and inventor.

TECHNICAL ASPECT

[0003] It is previously known to be able to control machinery andequipment at control desks which are connected via fixed connections orwireless connections. These proposals make use of the general controland supervision principles. With reference to control desk arrangementsproposed with CAN-protocol, the arrangements in question are primarilythose with wire connections. Reference is also made to U.S. Pat. No.5,392,454.

[0004] With machine-control and process-control systems of thiscategory, it is previously known that it is necessary to supervise theaggregates served by the modules such that in fault-searching, systemdesign, etc., it is possible to establish whether the equipmentcontrolled by a particular module is behaving as expected. It can bestated in this context that it may be necessary to monitor the functionsat valves, thermometers, etc., so that in certain functional states itcan be seen or registered whether the components in question areactually performing their expected function. It is also known to utilisemachine-control systems and process-control systems in which theequipment parts are connected via relatively long digital serialcommunications. The connection can also be established at locations andsites where accessibility is limited.

ACCOUNT OF THE INVENTION TECHNICAL PROBLEM

[0005] In the radio-controlling of machines operating with CAN-protocol,problems arise from the fact that the protocol calls for arbitration andconfirmation functions which are extremely time-critical. In order toensure that the modules do not misinterpret a particular message inquestion, in certain cases the receipt of a one over the connection mustresult, for example, in a zero being immediately presented to preventdisturbances occurring within the system. This calls for sending andreceiving to be effected simultaneously by one and the same module,which, in turn, calls for a full duplex connection and timesynchronisation between the sending and receiving channel in each moduleand predetermined maximum wave propagation time within the system. Thisis difficult to achieve in a radio system when such a system is oftenchosen to enable the distance between the modules within a system whichare connected by radio link to be easily varied. Radiocommunication istherefore less suitable for systems using the CAN-protocol. The objectof the present invention is to solve these problems.

[0006] In certain contexts, it is vital to be able to make use ofrepetition functions linked to machines or machinery stocks operatingwith CAN-protocol. At places which are difficult to survey or difficultto access, there is a need to build up an existing CAN-system andintroduce a repetition function over difficult stretches or to create ona temporary or longer term basis two separately working CAN-systemsinstead of one. In this context, there is a need to be able tofacilitate system developments and system applications. The object ofthe invention is to solve these problems also.

[0007] There is also a need to achieve effective coordination ofmachine-controls in machinery stocks, e.g. in weaving sheds in whichweaving machines have hitherto been controlled individually and providedwith their own man-machine interface such as control desks. There is awish to be able to introduce CAN-protocol into the control of machinesof this category, this having been hindered by the above-specifiedproblems. The object of the present invention is to solve these problemsalso and it is proposed, in respect of this category of machinery-stockcontrol, that the controls be effected via radiocommunication from andto a common man-machine interface, such as a control unit or controldesk. The control equipment is thereby simplified and a coordinated,effective control is able to be established in terms of service andproduction via or in the machinery stock.

[0008] Radiocommunication is often utilised between an operator'scontrol unit and the control system of the machine which he controls.Examples of such systems are radio-controlled airplanes,radio-controlled contracting machinery, radio-controlled hoistingcranes, etc. of various types. One problem is here to set up a radiochannel which is exclusively between control unit and machine, such thatthe connection is not disturbed by other operator/machine connections.The object of the present invention is to solve this problem also.

[0009] The invention also allows reduced susceptibility to theft andoffers high security within the system per se.

[0010] There is a great need to be able to carry out fault searches andtests on modules which are situated at a distance apart and in which afunctional effect upon a first module is wanted to be able to befollowed at a second module, and vice versa. For instance, there is adesire in certain situations to initiate controls at a master in theCAN-system in order to obtain manifestations at one or more slavemodules. There is here a need to see whether the function is beingcorrectly performed by the components or aggregates controlled by themodule in question.

[0011] There is also a need to be able to stimulate a component oraggregate at a module and to discover what repercussions this has.

[0012] There is also a need to be able to carry out registrationoperations in a fault-searching and testing context for a certainperiod, as well as to acquire direct visual and signal information atthe site for the module subjected to testing or fault-searching.

[0013] The above must be practicable even if the modules are far apartand hidden from each other. Preferably, the above will be able to beeffected via an already existing switching function, i.e. connectionsand disconnections do not need to be made in each separate case/inrespect of each module.

[0014] The invention aims to solve the whole or parts of the aboveproblems.

THE SOLUTION

[0015] What primarily can be considered to be characteristic of a deviceaccording to the invention is that it comprises two or morecommunication parts which form part of the CAN-system, respectivelybetween the CAN-system and the unit mentioned in the introduction, andwhich are communicable via one or more wireless connections, that when atransmission is made from a first communication part to a secondcommunication part, the parts operate with a signal protocol which takesno account of arbitration and/or confirmation function(s) found in theCAN-system. A particular receiving communication part executes orassists in the conversion of the said signal protocol to the signalprotocol of the CAN-system.

[0016] In one embodiment, the communication parts can be coupled to theCAN-system, which in the non-connected or non-activated state of thecommunication parts forms a unitary system and which in the connected oractivated state of the communication parts forms two CAN-systems whichoperate separately relative to each other.

[0017] A particular pair of communication parts can in this case operatewith a protocol which is distinct from the CAN-protocol and is bettersuited for radiocommunication, e.g. Aloha, Ethernet, the “GPSP”WaveRaider protocol from GEC Plessey in England, etc. In one embodiment,the invention is utilised in respect of a machinery stock. As an exampleof a machinery stock can be cited weaving machines which are installedin one or more weaving sheds and are respectively allocated one or moremodules. In this case, the unit can comprise a service unit common to anumber of weaving machines, preferably the majority or all of the totalnumber of weaving machines. This service unit can comprise or contain apersonal computer (PC).

[0018] In the case of weaving machines in a weaving shed, one or moremodules assigned to a weaving machine are connected to a servicefunction in the weaving shed. This service function can consist ofbeam-changing, bobbin-changing, etc. Service staff receive informationin parallel with a service machine which is appropriately connected tothe particular weaving machine. Function information can thereforeappear both on the unit and in control apparatus belonging to theservice machine, the function measure or instruction in question beingable to be prepared simultaneously or in perfect coordination betweenthe service machine and the staff involved. An effective synthesis isobtained for production and service measures which are necessary to theweaving machines in order to maintain effective production. The machinescan be coupled together in a control network in which a particularmachine has its own unique code and control system in order to preventdisturbances between the machines. The frequencies are preferably chosenwithin the broad-band range, i.e. 1 GHz or above, preferably the openISM-band, but IR-frequencies and ultrasound frequencies can also beused. The latter particularly in respect of acoustic communication in anunderwater environment.

[0019] The device according to the invention also relates to a system ofmutually separate units which are intercommunicable by means ofradiocommunications, these being able to be set up such that messagechannels can be realised between two or more of the said units. Theradio communications operate here with an identification system in whicha key allocation can be realised, which in a particular connectioninstance enables messages to be transferred between selected units only.The particular unit is further designed with a CAN-system (ControllerArea Network), in which activations, control operations, functions,stimulations, readings, etc. in modules making up the unit areintercommunicable via a digital serial connection. The latter device isprincipally characterised by the fact that in each connection instancethe key allocation between the units is based upon anidentity/identities which, during a connection process for theconnection in question, are acquired from a module in the CAN-systemconcerned and/or from a master system or master control centre. Furtherfeatures of the devices in question can be derived from the followingpatent claims.

[0020] What primarily can be considered to be characteristic of a deviceaccording to the invention, comprising the module mentioned in theintroduction, is that a radiocommunication apparatus is arranged forconnection with a part belonging to a second module in the system forthe establishment of a radiocommunication channel between the locationfor the placement of the first module and a location for the placementof the second module. At the location for the placement of the firstmodule, radiocommunication equipment can be activated for initiation viaa radio channel and the said part of the radiocommunication equipment byactivation of a signal in the second module. This signal activationcauses the first module to perform its particular control and/orsupervisory function which then becomes able to be observed orregistered in place of the first module.

[0021] In one embodiment, the CAN-system forms part of a machine-controlsystem and/or process-control system in which a first signal exchangeaccording to the CAN-protocol obtains between involved modules withinthe system for the control operation and the performance of the process.A first activation of the radiocommunication equipment at the firstlocation hereupon gives rise to a second activation of circuits in thesecond module. This second activation induces the said signal activationin the second module.

[0022] In a further embodiment, the signal activation caused by thesecond activation gives rise to message initiation in the second module,which prepares to dispatch a message via the module's communicationcircuit, over the connection to the first module. The second module ishereupon able to transmit the thus generated message, with apredetermined order of priority, in the ordinary message or signalexchange between the modules. In one embodiment, the second module cancause interruption to the ordinary message or signal exchange in theCAN-system. That signal activation in the second module which is hereininitiated by the second activation takes over the CAN-system for thegeneration and sending of one or more test messages via thecommunication circuit and the connection to the first module.

[0023] When its signal is activated on the basis of the secondactivation in the second module, the second module can imitate a controlor supervisory function which can normally be found in the machineand/or process-control system. Alternatively, or as a supplementthereto, a control and/or supervisory function which is especially cutout for the testing function is generated.

[0024] The radiocommunication equipment preferably operates two-way(half or full duplex). This makes it possible for a stimulation ofcontrol or supervisory component(s) or equipment at the first module toproduce a feedback to the second module, via the connection to thesecond module. The latter generates a stimulation-responding informationsignal, which is fed back to the radio equipment part situated at thefirst module. Information which is transferred via theradiocommunication equipment can thereby be indicated or presented on orat the said radiocommunication equipment part at the first module.

[0025] In one embodiment, the radiocommunication equipment part at thefirst module is connected to the control and or supervisory equipmentserved by the first module and/or directly to the module.

[0026] In one embodiment, the second module is arranged such that it ismerely a so-called “gateway” between the radiocommunication of the firstunit and the CAN-system, i.e. a message from the first module via radioto the second module is converted there to a CAN-message and transmittedon the bus, and vice versa.

[0027] Further characteristics derive from the following patent claimsand the description. The device also therefore works in cases where theequipment in the first module is stimulated, for example, manually,which stimulation can be monitored at the control orinformation-supplying unit to ascertain whether there are faults in theequipment and/or the communications.

ADVANTAGES

[0028] Radiocommunication between control units and machines inmachinery stocks can be economically established even where the machinesoperate with CAN-protocol. Repetition functions can be inserted into theCAN-system or the machine and/or process-control system, which meansthat connections can be established for even poorly accessiblelocations. Proven methods are in fact able to be used in connection withthe radiocommunication control operation, as regards control desks,frequency usage, security arrangements, coding, keys, etc.

[0029] The above makes it possible for testing and function-checking tobe easily carried out on CAN-modules, using simulated control operationsand stimulations which are introduced to second modules at a distancefrom the first modules. The checks can be executed even if theconnecting line is long, e.g. 800 m, or the modules are hidden from oneanother. The stimulations can also be carried out on the visuallysupervised module or its equipment/components and the reactions to suchstimulations can be obtained in a second direction within the CAN-systemand recorded at the location for the first module(s).

DESCRIPTION OF THE FIGURES

[0030] A currently proposed embodiment of a device exhibiting thecharacteristics which are indicative of the invention shall be describedbelow with simultaneous reference to the appended drawings, in which:

[0031]FIG. 1 shows radiocommunication between a unit and a CAN-system

[0032]FIG. 2 shows how a CAN-system with repetition function can bedivided into two CAN-systems,

[0033]FIG. 3 shows how a CAN-system can be arranged with a control unitwhich can work either directly connected to the CAN-bus and then utilisepower from this system or via a radio channel and then be powered from achargeable battery,

[0034]FIG. 4 shows transmitting and receiving units via a radio channelin a radiocommunication system, in which transmission takes place in aprotocol distinct from the CAN-protocol and in which conversion to theCAN-protocol is realised on the receiver side, and

[0035]FIG. 5 shows a simple system in which an operator control modulewhich works on the CAN-bus is easily modified from a wire-bound systemto a radio-controlled system,

[0036]FIG. 6 shows a device which enables a CAN-message to be convertedto a radio message, and vice versa,

[0037]FIG. 7 shows diagrammatically how protocol exchange takes placebetween the CAN-protocol and a radio protocol,

[0038]FIG. 8 shows a radiocommunication control system in respect of amachinery stock, e.g. in the form of weaving looms in a weaving shed,

[0039]FIG. 9 shows an arrangement for weaving machines in a weavingshed, in which information goes out to a service car in parallel with acontrol panel,

[0040]FIG. 10 shows a simple way of setting up a secureradiocommunication between a control member and a machine,

[0041]FIG. 11 shows a construction site with radio-controlled cranes andthe establishment of a radio connection between these and a particularoperator.

[0042]FIG. 12 represents a basic and block diagram of a CAN-system whichradiocommunication equipment parts are arranged at first and secondmodules in the system and in which the radiocommunication equipment hasbeen connected to the second module in order to simulate stimulationstherein, the effect of which upon the system can be monitored at thefirst module,

[0043]FIG. 13 shows in basic representation an antenna system for longtransfer distances in respect of equipment according to FIG. 1,

[0044]FIG. 14 shows in block diagram form the structure of the module 4Aaccording to FIG. 1, and

[0045]FIG. 15 shows in diagrammatic form the framework structure fordigital signals which are used.

DETAILED EMBODIMENT

[0046]FIG. 1 shows in basic representation a CAN-system 101A. By this ismeant a machine-control and/or machine-supervision system.Alternatively, a process-control or process-supervision system can beobtained. The CAN-system is represented by a number of modules 102A,103A, 104A, which serve their parts of the system in question. Alsoincluded are a control unit 105A and a radio module unit 106Aconnectable and connected to or forming part of the module 117A. Thesaid modules can intercommunicate via a digital serial communicationconnection 107A. FIG. 1 also shows a control desk function 108Acomprising operating levers 109A and 110A and a personal computer 111Awith possible display unit 112A. The unit 108A further comprises amodule 113A, which can be synthesised with the modules on the bus via aradiocommunication system comprising a part 114A, and possibly also anadjustment unit 118A, in the unit 108A and the said radio module 106A.The radio module 106A and the part 114A can comprise transmitter andreceiver, so that a two-way communication 115A, 116A is obtained.Communication takes place via established radio channels in theradiocommunication equipment and the latter operates preferably in thebroad-band range, see above. The units 116A and 114A are provided withantennae 106A and 114 aA for the said communication facility. Themodules 102A, 103A, 104A can in this case represent modules forming partof machines in a machinery stock in which a particular machine canoperate with a number of modules. There is therefore a possibility ofaccomplishing controls from the unit 108A of the modules in question viathe CAN-system. The said machines in the said machinery stock canconsist of weaving machines—described in greater detail below—installedin a weaving shed or of hoisting cranes within a construction area.

[0047]FIG. 2 shows how a CAN-system 201A having a repetition functioncan be arranged to fox two different CAN-systems 202A and 203A, therespective CAN-system here being equipped with radio modules, which cancomprise transmitter and receiver in accordance with the equipment 116A,117A according to FIG. 1. The radio modules have been given thedesignation 204A and 205A respectively. The first CAN-system has themodules 206A, 207A, 208A, 209A and the second CAN-system has the modules210A, 211A, 212A. Control functions can be performed via the modules210A, 211A and 212A, via the pilot pins 213A, 214A and a personalcomputer 215A. If the radio modules 204A and 205A are uncoupled, thenthe CAN-buses 216A and 217A of the sub-systems can be joined together toform a common CAN-bus 218A in which the junction point has been denotedby A. In the case of separate coupling and jump coupling, the CAN-busends would naturally have to be correctly terminated and a power supplysuitably arranged. Except for certain accruing delays to the message,the divided system will function as if it were coupled together withoutany changes in the system's software.

[0048]FIG. 3 shows a further variant of a CAN-system 301A with modules302A, 303A, 304A and 305A. Here too, radio modules 306A and 307A areutilised. The radio module 306A is tied to the CAN-system 301A, whilstthe radio module 307A is assignable to a further CAN-system 308A, whichcan be connected in two alternative ways to the CAN-system 301. The oneway is realised via a mechanical, galvanically separated or wirelessconnection 309A or via the radio modules 306A and 307A, which operate ina manner corresponding to the radio modules according to FIGS. 1 and 2.The CAN-system 308A is provided with three modules 310A, 311A and 312Afor the inputting and receipt of information which is relevant to thesystem in connection with control and/or supervision within the system.In this case, a battery system 313A is utilised to power the CAN-system308A. When the system 308A is used at a distance from the system 301Aand the radio connection is utilised, then power is supplied from thebattery system 313A. When the systems are coupled together, then thebattery system 313A is connected directly up to the power unit 315A ofthe CAN-system 301A via the inductive connection 314A and the batterysystem is then able to charge its integral accumulators. The CAN-system301A is coupled together with 308A by the connection 315A via aninductive coupling 316A. A system can thereby be coupled together orseparately coupled to form two sub-systems without mechanical connectorshaving pins and sockets, which often cause problems when exposed to wearand tear, corrosion and physical damage. In many cases, one and the samecontrol unit can operate either conventionally “fixed” mounted andconnected to the CAN-network or as a remote control unit. In the fixedposition the batteries are loaded. Whenever the unit is then wanted tobe used as a remote control unit, it is simply disconnected from thesystem. In the fixed-coupled position, the radio units have agreed onall parameters which are required for wireless communication. Anadvantage is also that the operating unit is able to be removed from thecontrolled unit and without a control unit the machine is difficult tosteal.

[0049]FIG. 4 shows a monitoring/control unit 401A, having one or moreCPU's 402A, memories 403A, a CPU-integrated or free-standingCAN-Controller 404A (for example Intel 527A), a CAN-driver 405A (forexample Philips 251A), communication adjustment circuits 406A, etc.,diagrammatically illustrated, built for the CAN-protocol, which areconnectable to a radio unit 408A and also connectable to aCAN-connection 407A. The radio unit 408A comprises two communicationparts, a radiocommunication part 409A having hardware and software,which enables a wireless communication to be set up between differentradio units, and a part having hardware and software, incorporating oneor more CPU's 410A, memories 411A, communication adjustment circuits412A, etc., diagrammatically illustrated, which allows communicationwith the unit 401A. Examples of such radio units are WaveRider from GEC(GB) and examples of a CAN-unit are CANnonBall and mini-CB from EVASERAB (SE). The radio part 408A and the CAN-part 401A have at least one CPUeach and can intercommunicate via a serial or parallel interface 413A.The parts 403A and 408A can be built together in a common casing 414A oreach in its own casing, indicated by 415A, and can be connected by aconnector 416A. An advantage of having the radio unit 408A and theCAN-Wait 401A mounted each in its own casing is that the radio unit canbe easily exchanged in the event of a fault, replaced by a similar radiounit in order to satisfy national or regional radiocommunicationregulations, or cam alternatively operate with some other wirelesscommunication based, for example, upon infra-red or visible light,ultrasound, etc. The CAN-part can in this case be a standard unit with aparallel or serial output which allows connection to a unit equivalentto 408A. Each radio part has a unique identity, in the case of WaveRideran Ethernet address, and each CAN-unit has a unique identity, forexample an EAN-number including a serial number. Each unit which will beable to be controlled also has a unique identity, for example anEAN-number including a serial number.

[0050] The radio unit operates independently as regardsradiocommunication and has a network protocol for this. All radio unitscan intercommunicate within radio range on a common channel. Two or moreradio units can be allocated or can themselves set up a channel which isexclusive to them. If further differentiation of the radio traffic isrequired, then two or more radio units can establish an exclusivemessage channel within a channel by the messages being encoded withtheir own common key. Each station can be allocated a station nameconstituted, for example, by a binary code or an ASCII-file. By havingtwo separate identification systems, one for radiocommunication and onefor CAN-communication, a very secure and flexile communication systemcan be established in which the system, apart from being a communicationsystem, can also be used to distribute and check the authority ofoperators to operate machines.

[0051] U.S. Pat. No. 5,392,454 describes how two radio units can set upa common exclusive communication channel by first seeking contact witheach other via another type of communication channel and by thereexchanging information about each other's unique identity. By markingits messages with its identity during ordinary communication, aparticular unit can thus filter out those messages which are intendedfor the unit in question. The fact that the identification of themessage is based upon the identity of the radio unit represents a majordrawback, firstly in respect of the exchange of radio units and secondlyif multicast-type connections are wanted to be set up. The consequenceof the solution proposed in U.S. Pat. No. 5,392,454 is that the radioconnection is tied between the transmitting and receiving radio unit andnot between operator unit and machine or between machine sub-system andmachine sub-system. The radiocommunication system can be regarded as themaster machine-control system. The radiocommunication units are regardedas special units within the system.

[0052] In CAN-systems, for example those operating with CAN HLP (HigherLayer Protocol) “CAN Kingdom”, it is usual firstly for each node ormodule in the system to have its own unique identity, which is based,for example, on an EAN-number and a serial number, and secondly forthere to be a module or node constituting a system node in the machinesystem. The identity of this node can also be used as identity for themachine. In the present invention, the radiocommunication unit isregarded as a CAN-node of whichever type, equating, for example, to avalve unit or a joystick unit. The radiocommunication system is thusregarded as the subordinate machine-control system. When the system isstarted up or as soon as a radio unit is connected to the system, thesystem node can detect this, for example by a method described in CANKingdom. Depending upon the situation, the system node can assign to theradio unit a general public network key or a unique key. A simple way ofconstructing a unique key is to base this upon the identity of some nodeincorporated in the system, since all of them have a unique identity,inclusive of the system node itself. If, for some reason, a node otherthan the identity of the system node is chosen as basis for theexclusive network key, then this is entirely possible, at least insystems based upon CAN Kingdom, with maintained system security, sincethe system node is aware of all integral nodes and no node can beexchanged and work within the system without the consent of the systemnode. From a security viewpoint, it is vital that it is the system nodeof that sub-system which is critical to security within the total systemwhich determines the network key and possibly also provides a jump planor alternatively a dispersion code, depending upon whether a jumpingfrequency or spread spectrum technique has been chosen. Examples of asuitable radio employing the latter technique is the “2.45 SpreadSpectrum Transceiver” from CRL Instrumentation in England. For example,in a system comprising a hoisting crane and a remote control unit, it isthe system node in the hoisting crane which has to assign the commonnetwork key to a particular radio unit, not any of the radio units orthe system node in the remote control unit. Alternatively, network keyscan be distributed at a still higher level within the system. Forexample, a unit which is common to a construction area can distributenetwork keys via a common channel to remote control units and cranes.The area-common unit then has complete information on all cranes and theidentities of remote control units within the area. It is vital that theradiocommunication units should be at a low level systematically withinthe machine system and hence fully exchangeable without security risk.The problems associated with radio transmission, such as, for example,jump plan, jumping frequency, dispersion code, identification of radiotransmitter and receiver, distribution of station identities, etc. canbe solved wholly within the radio system range and the machine systemconstructor needs only to ensure an adequate network key distribution. Ahierarchically structured machine system includes an organisation forthe generation and distribution of network keys and an organised way ofidentifying individual modules and groups of modules. The radio systemincludes an organisation for the generation and distribution ofcommunication channels and an organized identification of individualsand also possibly groups of radio stations. The fact that the machinesystem distributes the network keys and has scope to acquire and employinformation on the identities of stations forming part of the radiosystem means that radiocommunication in a CAN-system can be usedsecurely. The identity of the station in the radio network can beexchanged by the system node for the identity of the system node, inwhich case the system ceases to form part of the original radio network.

[0053] Having CAN-modules whose only tasks are to constitute units forwireless communication, hereinafter referred to as WCANM, is a majoradvantage in CAN-systems. An example: We have two wireless units, WCANM1and WCANM2. In stage one we couple them together via the CAN-connectionand they perform the start-up process and can subsequentlyintercommunicate in a secure manner. In a system which is traditionallyconstructed, then it is now possible to remove a unit, for example acontrol lever and monitoring unit, and replace this with a WCANM1. Theremoved module is now coupled together with WCANM2 and we have awireless connection between the monitoring/control unit and the rest ofthe system. In its simplest form, WCANM1 will now receive all messageson the CAN-bus. As and when a message is correctly received, it isrepackaged into a WCANM-message [sic] and sent to WCANM2, which unpacksthe message and converts it into a CAN-message and sends it to themonitoring/control module. This module cannot distinguish between amessage which has undergone these conversions and a message which hasarrived directly on the CAN-bus, if the CAN-Identifier is the same. Whenthe control/monitoring module sends a message, the reverse takes place.WCANM1 receives the message, repackages it, transmits it to WCANM1,which repackages and sends out the message on the CAN-bus.

[0054]FIG. 5 illustrates a process according to the above. A CAN-systemcomprises a CAN-bus 500A, to which the modules 501A, 502A, 503A, 504Aand 505A are connected. The module 505A is a control module to which thecontrol levers 508A and 509A are connected and with which the controlcommand can be given to 501A and 502A or 503A and 504A respectively. Bydecoupling the module 505A from the CAN-bus 500A and instead connectingup the radio module 511A and connecting the radio module 510A to theCAN-bus instead of the module 505A, a wireless connection has beenobtained between the control module and the CAN-bus.

[0055] Below and in FIG. 6, a detailed account is given of how aCAN-message is converted into a radio message and vice versa. A messageis created by the CPU 602 in module 601A and transferred to itsCAN-Controller 603A for dispatch. Apart from data, the CPU sendsinformation on the CAN-Identifier to which the data is to be coupled, onwhether this identifier is of the standard or extended type, on the factthat it is a data message and not a so-called “remote request” and onthe number of bytes which the data occupy in the data field. TheCAN-Controller converts this information into a bit pattern according tothe CAN-protocol, in which, inter alia, a CRC check code for the messageis worked out, and transmits the bit pattern 701A on the CAN-bus 600Aaccording to the rules of the CAN-protocol via the CAN-driver 604A. Oncethe CAN-Controller 607A of the WCANM-module 606A has correctly receivedthe message, then information corresponding to the CPU in module 601A isdownloaded to its CAN-Controller so as to be accessible to the CPU 608Aof the WCANM-module. This reads the received information and packages itinto a data format which is common to WCANM-modules: Bytes 0-3CAN-Identifier Byte 4 Data Length Code Bytes 5-12 Data Field 20

[0056] Note here that a CAN-Identifier is only a bit pattern and thatthe arbitration characteristic associated with this part of a messageaccording to the CAN-protocol is of no importance to the radiotransmission and that the CRC-code and acknowledgement bit are nottransferred. The data string 702A, in FIG. 7, according to the above istransmitted to the CPU 610A of the radio unit 609A via a local serial orparallel bus 611A for sending. (The interface 611A can comprise eightleads for data, six leads for handshaking, three in each direction, anda feedback signal lead for initiating the radio at the start-up of thesystem). The CPU 610A then deposits the data string as data according tothe protocol used by the radio units amongst themselves 703A. Here thedata are treated as whichever data and the CPU 610A is not thereforerequired to have any information on the CAN-protocol. The radio messagehaving been transmitted, the CPU in the radio unit of a receivingWCANM-module, following receipt according to the radio protocol, usesthe local bus to transmit the received data string 704A to the CPU ofits module's CAN-part. The CPU of the CAN-part then creates aCAN-message 705A in accordance with the format of the data string andpresents this to its CAN-Controller for dispatch on the CAN-bus and theprocess continues in the customary CAN manner. The CAN-Controllercalculates a new CRC check code and presents a one in theacknowledgement slot, since it is transmitter of a message which is newto this part of the system.

[0057] In CAN-systems constructed with CAN Higher Layer Protocol “CANKingdom”, an application in a module is tied together with aCAN-Identifier via a so-called “Folder” to allow the data exchangebetween applications in different modules to be coupled together. If theCAN-system is constructed according to CAN Kingdom, the Folder numbercan be used instead of the CAN-Identifier in the format of the datastring 702A and the Data Length Code omitted: Byte 0 Folder Number Byte1 - n Data n = 0 ... 8

[0058] Other necessary information derives from the particular “FolderLabel” in accordance with the CAN Kingdom protocol. The length of theether-borne message is thereby reduced. Furthermore, differentCAN-Identifiers can be used for the very same message in the varioussub-systems. This can be an advantage, since the priority of the messagecan then be adjusted to the conditions in the particular sub-system. Insystems developed for radiocommunication, only messages necessary to aparticular receiver are sent via radio and each sub-system has aninternal flow of messages between its nodes.

[0059] In CAN-systems it often happens that modules are set to receiveonly certain messages. This is generally done by filtering out certainbit patterns in the arbitration field of the CAN-protocol, which inspecification ISO 11898 is known as the Identifier Field. Since, from aCAN viewpoint, WCANM-modules can be quite ordinary CAN-modules, thesealso have the scope to filter out messages on the bus. If it is knownwhich messages are to be received on both sides of the wirelesscommunication, then WCANM1 and WCANM2 respectively can be set to filterout those messages which are to be received on the respective other sideand thereby reduce the load on the wireless connection. Since there isno known method of satisfying the time demands which are placed upon theacknowledgement bit of the CAN-protocol via a wireless connection with ahigh bit speed, typically 125 kb/s to 1 Mb/s, over longer distances,typically from a few meters up to five hundred meters, the wirelesscommunication is not bit-synchronous with the line-bound communication.Since the CAN-protocol is not followed in ether transmission, this canoften be done faster and with different scheduling of the messagetransmissions. If standard circuits for CAN are used, then it may beexpedient to take the message as it appears in the normal receptionbuffer which is read by the CPU, i.e. with CAN ID field, control fieldand data field, but without start bit, stuff bits, CRC bits, etc., andto transmit this according to a protocol suitable for wirelesscommunication. Another alternative is to receive from the CAN-bus entirebit streams and to buffer these as far as the acknowledgement bit. Whenthis is read to zero on the CAN-bus, the packet is transmitted via theether and, following receipt, the bit stream is transmitted on theCAN-bus an the reception side. From the acknowledgement bit onwards, thereceiving WCANM-module itself creates remaining bits according to theCAN-protocol. If, during this period, the first WCANM-module reads anerror frame after the acknowledgement bit during the remaining part ofthe CAN-message, then an error code is immediately transmitted to thereceiving WCANM-module, which then sends out an error frame on itsCAN-bus. This is an effective way of sending CAN-messages, since CAN'serror controls are utilised (and therefore no error control is requiredin the ether protocol) and there are few bits needing to be transmitted.The problem remains however, when some bit is incorrectly received fromthe ether or, worse still, a CAN-error arises on the CAN-bus belongingto the receiving side. It can then be too late for the receivingWCANM-module to send an error message over the ether. The originalmessage can already have been accepted on the sending side. This problemcan be solved in the CAN sigher Layer Protocol.

[0060] A further way of compressing the message which can be utilised,especially when the ether communication is operating at high bit speed,is for the bits of the CAN-message on the sending side to be received upto the point where the CRC-code and the stuff bits are removed, sincethese are not involved in the working-out of the CRC-code by the CANerror protocol. This packet is transmitted via the ether and, if theCRC-code is correct on arrival, then a CAN-bus is recreated.

[0061] The communication between WCANM-modules [sic] can be of the fullduplex or half duplex type. Full duplex offers the fastest transfer,since, if the receiver detects an error, it can immediately send back anerror message to the transmitter. In the case of half duplex, thereceiver would have to wait until the whole message is sent before areply can be given. Radio networks are most commonly of the half duplextype. A typical sequence is as follows: Transmitter Receiver 1. Set upconnection. 2. Acknowledgement 3. Sends message 4. Acknowledgement 5.Disconnect the connection

[0062] A more effective procedure is to send short messages constantlyto and fro between the transceivers. A CAN-message is always short incomparison to necessary information in a radio network protocol for the2.4 Gz band (the ISM band), in the order of magnitude of 11 to 154 bitsdepending upon the way in which the information is packed in the radioprotocol. It is therefore expedient for the CAN-information to beincluded in the “Establishment of connection” message and theacknowledgement message, thereby providing an effective use of thechannel. The fact that a short message is “ping-ponged” in this waymeans that a system-supervising node in the CAN-system has the chance tohave continuous information stating that the radio connection is intactand functioning. A broad-band communication further requires that theclock in a particular transceiver module shall in some way besynchronised with a real or virtual system clock. A constant exchange ofshort messages between stations in the system allows good precision tobe maintained in the system's clocks, thereby enabling the creation ofan effective broad-band protocol built on jumping frequency orbit-pattern synthesis and enabling the clock of the radio system also tobe used as a system clock within the CAN-system.

[0063] An ever increasing number of modern weaving looms are constructedwith a CAN-system. Each weaving loom has a display, a key set and veryoften also a memory card reader. These devices are utilised only when aperson operates them, i.e. for the vast majority of the time they aretotally redundant items of equipment. It is usual for one person to haveresponsibility for twenty or so weaving machines. Often all weavingmachines are connected to a network having a supervisory function andthe person in charge acquires information telling him which machine togo to in order to carry out some form of service. By connectingWCANM-modules to each weaving machine and a WCANM-module to a portableunit suitable for passing and taking information from a person, aso-called “Man Machine Interface (MMI), for example a portable personalcomputer, a number of advantages are attained. All displays, key setsand memory card readers can be removed. When the person stands at themachine, he connects his MMI to the CAN-network in the manner previouslydescribed. Since only one MMI is required per person, this can beconsiderably more powerfully designed than if there were one to eachmachine. Data files which were previously transferred using memory cardscan now be transmitted from the MMI. Fault analysis programs, graphicpresentation, tuning tool programs, etc. can be incorporated in the MMIand keyboards, mouse, etc. can be made user-friendly and upgraded moreregularly than the machines. Communication with the person often drawson greater computer resources than the machine-control function, so thatthe machine-control function can be made cheaper, more secure and moreeffective in that these functions are taken over by the MMI.

[0064] When the operator is not directly connected to a machine, he isconnected to the wireless network. As soon as a machine requires actionon the part of the operator, the machine sends out a message on thewireless network. The operator brings up on his display a list of allweaving machines which have requested assistance and for what reason. Ifmore than one machine has requested assistance, the operator can choosethe order in which he shall attend to the machines and he is alsoprepared for what has to be done so that he has suitable tools with him.

[0065]FIG. 8 shows a diagrammatic representation of a device accordingto the above. Each weaving machine 808A, 802A, 803A, 804A, 805A, 806Aand 807A is equipped with radio modules 801 aA, 802 aA, etc. and has ineach case an internal CAN-control system which can communicate with theradio module. The operator has a PC 808A to which a radio unit 808 aA isconnected. When the operator is supervising the plant, all radio unitsoperate on the same channel and information can be exchanged between thePC and all weaving machines. When the operator is working on a weavingmachine, the PC and the weaving machine use an exclusive channel, directcommunication with the weaving machine 801A being illustrated in thefigure. A further advantage is that the wireless network can replace thecurrently wire-bound network for production data to and from themachines and for supervision there-of.

[0066] The automation of a factory often incorporates various types ofdriverless trucks and similar equipment which also have an internalCAN-control system. These can also be connected up to the wirelesssystem. FIG. 9 shows a diagrammatic representation of a small part ofsuch a system with a weaving machine 902A, a driverless truck carrying areplacement beam 904A and an operator unit 903A. If, for example, a warpbeam is to be replaced, then a message 901A reporting this can pass fromthe weaving machine 902A both to the operator 903A and to the unit 904Atransporting replacement beams. This, in turn, can send a message 905Ato the operator about its status. When the operator arrives at themachine, the driverless truck with the replacement beam is alreadythere. In the event of further automatisation, the fixed machineinteracts automatically with the moving machine and the operator issummoned only if the machines, for some reason, have failed in theirtask.

[0067]FIGS. 10a and 10 b show an example of the above process. Amonitoring/control unit 1001A equipped with a radio unit 1001R isconnected via a CAN-bus 1002A to a machine 1003A equipped with a radiounit 1003R. The system-supervising node 1004A of the machine detectsthat a monitoring/control unit 1001A is connected to the machine andasks the system node 1005A of the unit 1001A for the EAN and serialnumbers of the monitoring/control unit and uses these to check whetherthe unit 1001A is of the right type and whether the individual isauthorised to control the machine 1003A. The method for carrying outsuch a check is, inter alia, described in CAN Higher Layer Protocol “CANKingdom”. If another monitoring/control unit 1006A already has controlover the machine, the connected unit 1001A is denied furthercommunication with the system in the machine 1003A. If no previousmonitoring/control unit has control and type and possibly also the newindividual is authorised to control the machine, then the machinetransmits a unique station name 1007A, for example the EAN-number,inclusive of serial number, of the unit 1001A. This station name issubsequently used jointly by the machine and the monitoring/control unitas identity for their communication channel. The CAN-connection 1002A isdisconnected and communication can be made via radio as shown in FIG.10b. FIG. 10b has revealed that the radio units 1001R and 1003R havebeen exchanged for the compatible units 1011R and 1010R aftercommunication has been established. This is totally feasible by virtueof the fact that a particular system node 1005A and 1004A delivers theagreed channel code to the respective new radio units, once these havebeen connected to the respective CAN-network.

[0068]FIG. 11 shows a more complex process. A company has a number ofcranes 1101A, 1102A, 1103A at a work site. All cranes have a uniqueidentity, 1 i, 2 i, 3 i and are each equipped with a radio unit 1 r, 2r, 3 r. Each crane operator 1104A, 1105A, 1106A has his ownmonitoring/control unit with radio. Each such monitoring/control unithas a unique identity, 4 i, 5 i and 6 i respectively. Whenever a cranedoes not have active connection with a control unit, it listens in an achannel 1107A which is common to the work site. Whenever a crane, inthis instance the crane 1102A, is assigned to a crane operator, in thisinstance 1106A, a central radio unit 1108A seeks contact with theassigned crane 1102A, which is identified by 2 i, and informs the craneoperator 1106A of the identity of the monitoring/control unit, 6 i oralternatively the network key based on 6 i. Once the crane operator ison the spot, he starts up his monitoring/control unit. The crane unitseeks contact on the general channel with the selectedmonitoring/control unit 1006A having the identity 6 i and when they havemade contact with each other the crane reports its identity 2 i and thefact that it is master of the connection. A connection is then set up onan exclusive channel 1109A, i.e. the crane communicates how frequencyjumping is to be done. In brief, it is therefore the case that craneswhich do not have contact with a selected control unit, in terms ofradiocommunication, comply with the jumping frequency from a centralunit. Once contact is obtained with a selected monitoring/control unit,the crane establishes contact with this, leaves the central unit andassumes control over the generation of frequency jumping. Themonitoring/control unit complies with this. If the radio connection isof the “spread spectrum” type, then the dispersion code is given insteadof the jump plan.

[0069] A plurality of control units cam be assigned to one and the samecrane. They then belong to the same network. In the working range of thecrane, a particular monitoring/control unit is assigned to apart-region. The part-regions can be partially overlapping or the cranecan follow a predetermined path between the part-regions. The crane isthereby able to be reliably controlled at a number of sites. When theload enters into a part-region, it obeys only that control unit which isresponsible for the area. There are a number of ways of solving theallocation of who has control over the machine on a given occasion. Afurther alternative is that the machine, after a certain period in whichno control command is forthcoming, for example two seconds, accepts thatparticular transmitter, of those which are accepted, which first issuesthe control command. The machine then obeys this transmitter until suchtime as it has failed to give any control commands for a two secondperiod.

[0070] In systems, especially those which are constructed according tothe principles contained in CAN Kingdom, in which a plurality of remotecontrol units are able to operate one and the same unit, controlcommands from a particular remote control are assigned to aCAN-Identifier by the system node of the controlled unit. The controlcommands are in this case first received by the system node, which, inturn, transmits control messages on the CAN-bus of the machine. Thesystem node can receive control commands from all remote control unitswhich communicate on the network key common to the machine and can thenselect which remote control unit's control commands will be implementedaccording to a set of rules, for example the work area within which theunit is situated or, quite simply, that the remote control unit whichfirst gives a shift command then retains control until it issues a codefor relinquishment of the control, is shut off or remains inactive for apredetermined period. Thereafter, the system node of the machine waitsfor a first best command from any of the authorised remote control unitsand then executes control commands only from this latter until theparticular emote control unit hands over control according to the above.

[0071] In a number of machines, for example process machines, a largenumber of measuring points and adjusting appliances are apparent, whichare geographically dispersed and on many occasions poorly accessible.The operator sits in a room in which he supervises and controls theentire system via VDU's. Whenever something is detected which calls foron-the-spot observation, a communication problem arises. For example, aclosed position of a valve is indicated, which should be open. When theoperator mikes an on-the-spot visual inspection, he sees that the valveis open. Has it opened whilst he was on his way to the valve or is thevalve signalling a closed position despite the fact that it is open? ofnow a WCMNM-module [sic] is connected and he has a MMI as previouslydescribed, then he can read on the spot the message which the valve istransmitting on the CAN-bus and decide whether there is a fault with thevalve or not. The WCANM-module connected to the CAN-bus, from theviewpoint of the CAN-signal, can be in a totally passive mode, i.e. nottransmitting a single bit, not even an acknowledgement bit. It can alsohave a CAN-active mode, so that the operator from his MMI is able tocommand the valve to open or close so as to monitor its functioningthere on the spot. Of course, the control system for the process plantwould have to be made such that the operator's actions do not jeopardisethe security of the process.

[0072]FIG. 12 illustrates a machine-control and/or process-controlsystem with its modules 1A, 2A, 3A and 4A, which are intercommunicablevia a serial digital connection 5A in a manner which is known per se. Inorder to simplify representation, the designation “CAN-system” isapplied to this system. According to the invention, the module servesaggregates forming part of the said machine-control system and/orprocess-control system. In FIG. 12 a valve in the aggregate is indicatedby 6A and a thermometer in the aggregate by 7A. The length L of theconnection 5A can be relatively long and can stretch over 200 m, forexample. The modules and aggregates in the system can also be situatedout of sight of each other.

[0073] In systems of this category, there is a need to be able toinitiate a fault-searching, testing, control operation, etc. at thefirst module 1A. Such fault-searching or equivalent can require eastsecond modules in the system need to be stimulated or need to establishsignal transmissions or signal receptions at certain stages of thefault-search or equivalent. In order to save staff, a radiocommunicationapparatus is used, comprising two radiocommunication equipment parts 8Aand 9A. The first part 8A can be independent from the CAN-system, whilstthe communication part 9A is connected to or forms part of the secondmodule. The connection between the part 9A and the module 4A can hereinbe made via a connection 101A, which can consist of a physicalconnection, non-galvanic connection, wireless connection, etc. Themodule 4A can be temporarily or permanently connected to the CAN-bus.The radiocommunication equipment 8A, 9A operates, where appropriate,with two-way connections 11A, 12A. The communication equipment 8A, 9Acan in this case utilise one or more channels, with use preferably beingmade of radio channels in the broad-band range, i.e. in the range offrequencies above 1 Gz, for example the ISM-band. The radiocommunicationequipment part 8A is provided with a control panel 13A, which can be ofa type which is known per se. The panel is connected to the transmittingand receiving unit 14A of the part 8A, which incidentally can be ofidentical type to 9A, via an adjusting unit 15A. As a supplementthereto, the panel can be directly connected to the aggregate orcomponents served by the first module 1A. This connection is effectedvia a second adjustment unit 16A and the connection per se is symbolisedby 17A.

[0074] An initiation i1 at the panel 13A induces an activation of thetransmitting part 14A, which, via a channel 11A, transmits theactivation to the radio receiver part 9A. This receipt gives rise to asignal generation i2 to the module 4A via an adjustment unit 23A. Themodule contains a microprocessor 18A, which causes a signal message 19Ato be generated, which is then transmitted to the connection 5A via thecommunication circuit 20A of the module 4A (see FIG. 1). Thetransmission can be made according to an order of priority which isdetermined by the CAN-protocol and in which the module, after admissionto the connection 5A, is able to transmit the message in question to thefirst module. Once the message 19A is received in the first module, afunctional stimulation of the component 6A, 7A or the equipment inquestion is realised, which functional stimulation is provoked by theinitiation i1 at the control panel. The control operation can in thiscase comprise a reversal of the valve 6A, a raising or lowering of thetemperature 7A, etc. The said reversal or temperature change can bevisible to an observer at the first module. Through stimulations of hiscontrol unit 13A, the observer is therefore able to obtain visualevidence of whether the control system in question is accomplishing whatit is meant to. At the control unit 13A, information 13A can also beobtained from the components or aggregate served by the module 1A. Bykeeping the radiocommunication equipment connected, registration andviewing can be carried out for shorter or longer periods of time.

[0075] Alternatively, a manual, electrical or other stimulation of thecomponents or of the aggregate served by the first module 1A caninitiate a message 21A generated in the first module, which message istransmitted to the second module 4A via the communication circuit 22A inthe first module and the connection 5A. The said signal message 21Ainduces a signal initiation i4 in the second module and activation ofthe transmitter part in the radiocommunication equipment part 9A. Via achannel 12A, the information in question is transmitted to the receivingpart in the radiocommunication part 14A and thereupon gives rise to thegeneration of an information signal is to the adjustment unit 15A, foronward conveyance to the control unit 13A or an information-supplyingunit at which the information is displayed or registered. A location orsite for the first module 1A is indicated by A, whilst a correspondinglocation or site for the module 4A is indicated by B. After the operatorhas carried out a check or fault-search at module 1A, he can proceed tomodule 3A, for example, and carry out equivalent work, providing thatthe module 4A is kept connected. He does not in this case need toconnect any equipment to the CAN-bus, but can continue to use theradiocommunication equipment 9A to transmit suitable messages andreceive chosen messages on the CAN-bus, via the still connected units 4Aand 9A. For communication over very long distances, up to a fewkilometers, it may be necessary to have directional receiving antennaein order to satisfy standards relating to maximum transmitted power.FIG. 13 shows such an arrangement for radiocommunication units ofpreviously described type, 24A and 25A, which are each equipped with anomnidirectional transmitter antenna 24 aA and 25 aA respectively and adirectional antenna 24 bA and 25 bA respectively. Other equipment inFIG. 1 is symbolised by 4A′ and 8A′.

[0076]FIG. 14 shows a diagrammatic representation of amonitoring/control unit 201A (cf. 4 in FIG. 1), having one or more CPU's202A, memories 203A, a CPU-integrated or free-standing CAN-Controller204A, a CAN-driver 205A, communication adjustment circuits 206A, etc.The unit 201A is built for the CAN-protocol and is connectable firstlyto a radio unit 208A and secondly to a CAN-connection 207A. The radiounit 208A comprises two diagrammatically illustrated communicationparts, a radiocommunication part 209A having first hardware andsoftware, which enables a wireless communication to be set up betweendifferent radio units, and a second part having hard and software,incorporating one or more CPU's 210A, memories 211A, communicationadjustment circuits 212A, etc., which allows communication with the unit201A. Examples of such radio units are WavreRider from GEC Plessey (GB)and examples of a CAN-unit are CANnonBall and mini-CB from KVASER AB(SE). The present invention can be implemented using these standardunits. The radio part 208A and the CAN-part 201A have at least one CPUeach and can intercommunicate via a serial or parallel interface 213A.The parts 201A and 208A can be built together in a common casing or, asin FIG. 5, can be applied each in its own casing 214A and 215A, and canbe mutually connected by a connector 216A. An advantage of having theradio unit 208A and the CAN-unit 201A mounted each in its own casing isthat the radio unit can be easily exchanged in the event of fault andreplaced by a solar radio unit in order to satisfy national or regionalradiocommunication regulations. The CAN-part can in this case be astandard unit with a parallel or serial output which allows connectionto a unit equivalent to 208A. If WaveRider is chosen as the radio part,the interface 213A will consist of eight lines for data, a so-called“data bus”, six lines for handshaking (three in each direction) and oneline for a feedback signal for initiating the radio when the system isstarted up. Each radio part as a unique identity, in the case ofWaveRider an Ethernet address, and each CAN-unit has a unique identity,for example an EAN-number including a serial number. Each unit whichwill be able to be controlled also ha a unique identity, for example anEAN-number including a serial number.

[0077] Data transfer of an eight-bit byte from the CPU 202A to the CPU210A is effected such that 202A activates an interruption signal to210A, which responds with an acknowledgement signal indicating that itis ready to receive data. (Otherwise a signal is activated whichsignifies “try again once more”). 202A presents a byte on the data busand activates the signal “data are accessible”. 210A reads the byte,acknowledges the transfer and stores it away in the memory 211A. This isrepeated until all of the byte is transferred. Transfer from 210A to202A is carried out in reverse.

[0078]FIG. 15 describes a detailed illustrative embodiment of signallingfrom a module corresponding to the panel 13A according to FIG. 1,generation of a message and the shaping of the message and its insertionon the bus and reception [lacuna] a module corresponding to 1A. FIG. 15shows only an operator unit 301A connected to a communication unit 302Avia a CAN-interface 303A and a communication unit 304A and a valve withcontrol electronics 305A connected to a CAN-bus 306A. Other modulesconnected to 306A are not depicted, but the total system corresponds tothat shown in FIG. 1. Both the units 302A and 304A each constitute acomplete radio unit corresponding to the whole of the device in FIG. 2,i.e. the radio unit can send and receive a message both via a CAN-busand via the ether. A modulation command to the valve 305A (cf. 6 inFIG. 1) is generated from the operator unit 301A and is transferred as aCAN-message 307A to the CAN-Controller of the communication unit, whichforwards the data 308A to the CPU in the CAN-part. This creates amessage 309A formatted for the radio part. 309A is described in detailby 310A, which has the following byte sequence: an overhead block withthe parts 321A and 322A, in which 321A comprises two bytes 311A whichindicate the number of bytes making up the message inclusive of 311A, atwo-byte sequential number 312A (for suppression of subsequent multiplytransmitted radio messages) and a six-byte long destination address313A, a six-byte long consignor address 314A, two bytes 315A indicatingthe number of bytes of user data 316A to follow, and the part 322A madeup of two or three bytes 317A which conclude the string. The user data316A are the same as 308A. The CPU in the radio part takes charge of thearrived string and converts it into a radio message 318A with anecessary overhead 319A—for setting up and synchronising the radiotransfer—and 320A for concluding the sequence and ensuring it wascorrect in terms of the CRC check total, etc. The radio overheadincorporates the information 321A and 322A. The radio module in thecommunication unit 304A receives the string 318A and recreates thestring 310A, this being transferred to the CPU of the CAN-unit, whichextracts 323A and creates the information for the CAN-Controller, whichthen, in turn, presents the CAN-message 324A on the CAN-connection 306A.The valve unit 305A now receives the command via the CAN-connection andimplements the same, which can be verified by the operator.

[0079] The invention is not limited to the embodiment shown by way ofexample above, but can be subject to modifications within the frameworkof the subsequent patent claims and the inventive concept.

1. Device in a CAN-system (standard ISO 11898), comprising modules(102A, 103A, 104A) which are intercommunicable via a digital serialcommunication (107A) and in which a control and/or supervisory functioncan realised from a first module or from a unit (108A), which iscommunicable with the CAN-system, belonging to one or more secondmodule(s), characterised in that it comprises two or more communicationparts (106A, 114A) which form part of the CAN-system, respectivelybetween the CAN-system and the said unit, and which are communicable viaone or more wireless connections, in that when a transmission is madefrom a first communication part (114A) to a second communication part(106A), the parts operate with a signal protocol which takes no accountof arbitration and/or confirmation function(s) found in the CAN-system,and in that a particular receiving communication part (106A) executes orassists in conversion of the said signal protocol to the signal protocolof the CAN-system.
 2. Device according to patent claim 1, characterisedin that the communication parts (204A, 205A) can be coupled to theCAN-system, which in the non-connected-up or non-activated state of thecommunication parts forms a unitary system (201A) and which in theconnected-up or activated state of the communication parts forms twoCAN-systems (202A and 205A) which operate separately relative to eachother.
 3. Device according to patent claim 1 or 2, characterised in thata particular pair of communication parts (204A, 205A) operates with aprotocol which is distinct from the CAN-protocol, e.g. Ethernet,WaveRaider, etc.
 4. Device according to any of the preceding patentclaims, characterised in that the modules are assigned to weavingmachines which are installed in one or more weaving sheds and arerespectively allocated one or more modules, and in that the unitcomprises a service unit common to a number of weaving machines,preferably the majority of the total number of weaving machines, thesaid service unit preferably comprising or containing a personalcomputer (PC).
 5. Device according to any of the preceding patentclaims, characterised in that one or more modules assigned to a weavingmachine in a weaving shed are arranged such that they are connected viaradiocommunication to a service function, which service functioncomprises or involves beam-changing, bobbin-changing, etc.
 6. Deviceaccording to patent claim 7 [sic], characterised in that the servicefunction comprises a service machine for the said function, whichservice machine can obtain up-to-date service function information inparallel with the latter function information appearing on the unit, thefunction measure or instruction in question being able to be preparedsimultaneously or in perfect coordination between the service machineand the staff involved.
 7. Device according to any of the precedingpatent claims, characterised in that the unit provides information onfaults occurring to a weaving machine in the weaving shed.
 8. Deviceaccording to any of the preceding patent claims, characterised in thatthe production which is attainable with weaving machines in a weavingshed and the service measures which are necessary to the weavingmachines in order to maintain effective production can be synthesisedwith the aid of the unit.
 9. Device according to any of the precedingpatent claims, characterised in that where there are a number ofmachines (weaving machines) controlled by a common control unit, theyare coupled together in a control network in which a particular machinehas its own unique control frequency in order to prevent the variousmachines being disturbed by one another's frequencies.
 10. Deviceaccording to any of the preceding patent claims, characterised in thatthe frequencies are chosen within the broad-band range, i.e. 2.4 GHz orabove.
 11. Device in a system of mutually separate units, e.g. machines(1101A, 1103A) at a construction site, weaving machines (803A, 804A).etc., which are intercommunicable by means of radiocommunications (115A,116A), these being able to be set up such that message channels can berealised between two or more of the said units, and in which the radiocommunications operate with an identification system in which a keyallocation can be realised, which in a particular connection instanceenables messages to be transferred between selected units only and inwhich a particular unit is designed with a system operating essentiallywith a CAN-signal protocol (standard ISO 11898), here referred to as aCAN-system, in which functions, stimulations, readings, etc. in modules(102A, 103A, 104A) making up the unit are intercommunicable via adigital serial connection (107A), characterised in that in eachconnection instance the key allocation between the units is based notupon the real identity of equipment performing the radiocommunication(s)but upon identity/identities assignable to the equipment, whichidentity/identities are brought about during coupling by a module in theunit involved and/or from a master system or master control centre. 12.Device according to patent claim 11, characterised in that therespective module concerned (401A) is arranged such that akey-allocation-performing function is built into the module and/or isassignable to the module from a master system or systems (1108A). 13.Device according to patent claim 11 or 12, characterised in that themodules in the CAN-system of a particular unit have unique identities,and in that the unique identity/identities of one or more modules in theCAN-system forms the identity/identities for particularradiocommunication-performing equipment (e.g. 204A, 205A).
 14. Deviceaccording to any of preceding patent claims 11-13, characterised in thata particular CAN-system comprises a radio module (204A), forming part ofradiocommunication (115A)-performing equipment, and in that theCAN-system is arranged so as to detect when the radio module isconnected or activated, key allocation being able to be realised fromanother particular module in the CAN-system belonging to the activatedor connected radio module.
 15. Device according to any of precedingpatent claims 11-14, characterised in that the key allocation comprisesallocation of a public key, common to CAN-systems incorporated within anarea, or a unique key, which therefore is based upon the identity of amodule forming part of any of the CAN-systems which communicate by radioamongst themselves.
 16. Device according to any of preceding patentclaims 11-15, characterised in that the key allocation is carried out bya system node (601A) selected within the CAN-system, which is aware ofall nodes forming part of the CAN-system and in which no node can beconnected or exchanged or work within the system without the consent orknowledge of the system node.
 17. Device according to any of precedingpatent claims 11-16, characterised in that the system node determinesnetwork keys, the jump plan and/or dispersion codes in theradiocommunications.
 18. Device according to any of preceding patentclaims 11-17, characterised in that where there are units in the form ofa machine, e.g. hoisting crane (1101A) and remote control unit (1104A),the system node in the CAN-system of the machine unit is arranged so asto determine a common key for both units (1103A, 1104A).
 19. Deviceaccording to patent claim 18, characterised in that the network keys canbe distributed exclusively, alternatively or as a supplement from asuperordinate level, e.g. via a common communication channel (1107),e.g. in the form of a radio channel, for a number of machines (hoistingcranes) and remote control units (1104A, 1105A, 1106A), the area-commonunit having complete information on the identities of all machines andremote control units within a particular area and the radiocommunicationequipment ending up at a low level from the system viewpoint and beingable to be exchanged without any security risks.
 20. Device according toany of preceding patent claims 11-19, characterised in that in caseswhere a number of remote control units (1104A, 1105A) are arranged so asto control a common unit (hoisting crane, weaving machine, etc.), aparticular control command from a particular remote control unit isassignable or receivable in an identification device (bit pattern) inthe controlled common unit, which identification device is preferablydisposed in the system node of the controlled unit.
 21. Device accordingto patent claim 20, characterised in that the control command can bereceived with the aid of a network key assigned to the controlling unit,and in that the system node selects the control command of a particularremote control unit according to a predetermined set of rules, whichallow the remote control units to be connected at different time stages.22. Device according to any of preceding patent claims 11-21,characterised in that a number of machine units (1101A, 1102A, etc.) areassignable to a number of remote control units (1104A, 1105A) allocatedto various individuals, in that where there are non-activated machineunits these are arranged so as to listen in on a common channel assignedto a work site (1107A), in that whenever an idle machine (e.g. 1101A) isassigned to a remote control unit (e.g. 1104A) (individual) a radiocentre establishes contact with the idle machine and transfers theparticular identity/keys to the remote control unit, in that wheneverthe remote control unit is activated the radio part of the idle machineestablishes contact with the radio part of the selected remote controlunit via the universal channel (1107A) and reports its identity and thefact that it is master of the connection, and in that an exclusivechannel between the machine unit and the remote control can in this casebe set up, in which exclusive channel information on the jump plan, forexample, is transferred.
 23. Device according to any of preceding patentclaims 11-22, characterised in that the CAN-system is arranged withradio modules (WCANM) (606), the sole task of which is to attend to thewireless radiocommunications.
 24. Device according to any of precedingpatent claims 11-23, characterised in that a plurality of remote controlunits (1104A) each serve their own part-area within a work area, and inthat, where a mobile unit is controlled by the area, control over themobile unit is passed from one remote control unit (1104A) to anotherremote control unit (1105A) as it passes through a part-area border. 25.Device according to any of preceding patent claims 11-24, characterisedin that a module comprises a CPU containing a monitoring/control unit(401A), memories, a CAN-Controller (404A), a CAN-driver (405A) andadjustment circuits (406A) for communication via a CAN-connection(407A), which monitoring/control unit can be coupled together via aconnector (416A) to a radio unit comprising a radio communication part(408A) and a communication part (409A), the last-named of whichcomprises a CPU (410A), memory (411A) and adjustment circuits (412A) forcommunication.
 26. Device according to any of preceding patent claims11-25, characterized in that where there are a plurality of machines,e.g. weaving machines (803A), which are served by a control desk unit(808A), a machine which requires action sends a message on the wirelessnetwork/radiocommunication network, and in that at the control desk unit(808A) one or more items of information appear on the number of machinesrequiring assistance, the identity of the machines and the nature of theaction, etc., a selection facility being provided at the control deskunit for a choice of running order for serving the machines in need ofaction.
 27. Device according to patent claim 26, characterised in thatwhere there is a supervisory function from the control desk (808A) allmachines make use of the same radio channel and when a selected machineis serviced an exclusive radio channel is established between theselected machine and the control desk unit.
 28. Device in a CAN-system(standard ISO 11898), comprising modules (1A, 2A, 3A, 4A) which can beconnected via a digital serial communication (5A) and in which afunction in a first module (1A) and/or equipment unit(s) controlled bythis is/are intended to be able to be observed or registered at alocation (A) for the placement(s) of the first module (1A) and/or of theequipment unit(s), characterised in that a radiocommunication equipment(8A, 9A) is arranged for connection with a part (9A) belonging to asecond module (4A) in the system for the establishment of aradiocommunication channel (11A, 12A) between the first-named location(A) and a location (B) for the placement of the second module (4A), andin that, instead of the placement(s) of the first module and/or of itsequipment unit(s), the radiocommunication equipment (8A, 9A) can beactivated for initiation (i1) via a radio channel (11A) and the saidpart (9A) of the radiocommunication equipment by the activation of asignal (i2) in the second module, which signal activation (i2) inducesthe first module (1A), where there are no faults in the system, toperform its particular control and/or supervisory function, which inthis case can be observed or registered at the location for the firstmodule and/or its equipment unit(s).
 29. Device according to patentclaim 28, characterised in that the CAN-system forms part of amachine-control system and/or a process-control system in which a firstsignal development (i5) obtains between the modules in the system forthe performance of the particular process of the control system, and inthat a first activation (i1) of the radiocommunication equipment at thefirst location (A) gives rise to a second activation of circuits in thesecond module (4A), and in that the second activation gives rise to thesaid signal activation (i2) in the second module.
 30. Device accordingto patent claim 9, characterised in that the signal activation (i2)caused by the second activation gives rise to message initiation (19A)in the second module, which prepares for message transmission via thecommunication circuit (20A) of the module over the connection (5A) tothe first module (1A).
 31. Device according to patent claim 30,characterised in that the second module transmits the thus generatedmessage (19A) according to a predetermined order of priority in theordinary exchange of messages or signals (i5) between the modules. 32.Device according to patent claim 31, characterised in that the secondmodule causes an interruption in the ordinary exchange of messages orsignals (i5) within the CAN-system, and in that the signal activation(i1) in the second module (4A), initiated by the second activation,takes charge of the generation and dispatch via a communication circuit(20A), the connection (5A) to the first module (1A), of one or more testmessages.
 33. Device according to any of the preceding patent claims,characterised in that the second module, when a signal is activated (i2)on the basis of the second activation in the second module, imitates acontrol or supervisory function, which normally can occur in the machineand/or process control, and/or generates a control and/or supervisorycontrol operation which is especially cut out for the testing orfault-searching function.
 34. Device according to any of the precedingpatent claims, characterized in that the radiocommunication equipment(8A, 9A) operates with two-way connections (11A, 12A) such that astimulation of a controlled or supervised component or aggregate at thefirst module (1A) produces a feedback from the first module via theconnection (5A) to the second module (4A), whereby an information signal(i3) representing the stimulation is generated, which information signalis transferred to the radio equipment part (9A) situated at the secondmodule, information which is transferred in this way via theradiocommunication equipment being indicated or presented on or at theradiocommunication equipment part (8A) at the first module.
 35. Deviceaccording to any of the preceding patent claims, characterised in thatthose equipment parts which can be observed or registered at the firstmodule comprise components, e.g. valve(s), thermometer(s), etc. 36.Device according to any of the preceding patent claims, characterised inthat the radiocommunication equipment operates at high frequencies, e.g.frequencies of 2.4 GHz or more.
 37. Device according to any of thepreceding patent claims, characterised in that the radiocommunicationequipment part (8A) at the first module (1A) is connected to thosecontrol or supervisory equipment part(s) served by the first module. 38.Device in a CAN-system (standard ISO 11898), comprising modules (1A, 2A,3A, 4A) which can be connected via a digital serial communication (5A)and in which a function in a first module (1A) and/or equipment unit(s)controlled by this is/are intended to be able to be observed orregistered at a location (A) for the placement(s) of the first module(1A) and/or of the equipment unit(s), characterised in that aradiocommunication equipment (8A, 9A) is arranged for connection with apart (9A) belonging to a second module (4A) in the system for theestablishment of a radiocommunication channel (11A, 12A) between thefirst-named location (A) and a location (B) for the placement of thesecond module (4A), and in that at the location for the placement of thefirst module the equipment unit(s) of the module is/are arranged suchthat they can be stimulated by means of the stimulation, e.g. withelectrical and/or manual stimulation, in that the said stimulationinitiates the transmission of a message (21A) generated or present inthe first module (1A) over the connection (5A) to the second module(4A), and in that the said message hereupon induces activation of theradiocommunication equipment (8A, 9A) and transfer of an item ofinformation responding to the said stimulation to aninformation-supplying unit (13A), which delivers the information inquestion.
 39. Device according to patent claim 38, characterised in thatthe information in question makes it possible for a user to decide uponthe relationship between the stimulation and the information.
 40. Deviceaccording to patent claim 39, characterised in that the said stimulationinduces a signal emission (i3) via a fixed connection (17A) establishedbetween the first module (1A) and the information-supplying unit (13A),and in that the said information and signal-emission can be compared atthe information-supplying unit in order to discover any defectiveness inthe communication path via the serial communication (5A), the secondmodule (4A) and the radiocommunication channel (12A).